Formulation and optimization of pulley-gear-type SMA heat engine toward microfluidic MEMS motor

In this paper, we modeled and analyzed the shape-memory-alloy (SMA) heat engine in steady state. The heat engine is composed of two pulleys, three gears, and an SMA coil spring. We formulated an expression that optimizes the relationship among the parameters for the maximum power and the torque of the heat engine. This article is the first to present the basic procedure to solve the optimal solution for the pulley-gear-type heat engines that are driven by an SMA coil spring. We also discuss the miniaturization of the heat engine to actuate the Bio MEMS and the micro TAS devices as fluidic MEMS actuators.